Overview
Carbamazepine (Carbatrol, Equetro, Tegretol) is prescribed for the control of a variety of seizure disorders.
It is also used as a special kind of pain reliever for trigeminal neuralgia which produces severe facial pain.
Although the Food and Drug Administration has not approved carbamazepine for other uses, doctors sometimes prescribe it for a variety of psychiatric disorders, alcohol withdrawal and restless leg syndrome.
Side Effects
Side effects associated with carbamazepine include dizziness, drowsiness, incoordination, unsteadiness, mood changes, nausea, vomiting, stomachache and loss of appetite.
Other adverse reactions to be alert for include dry mouth, constipation, rash, itching, fatigue, headache, blurred vision, ringing in the ears, double vision, numbness and tingling of the hands and feet, swollen legs and feet, heart failure, high blood pressure, fainting and sexual problems. Heart rhythm abnormalities, lung reactions, pancreatitis and low sodium (hyponatremia) are serious complications of carbamazepine.
Carbamazepine can rarely cause failure of the bone marrow to produce blood cells appropriately. Symptoms include unexplained sore throat with fever and chills, mouth ulcers, and aching joints and muscles. Since this is a life-threatening reaction, such symptoms should be reported immediately to a health care professional.
Skin reactions such as Stevens-Johnson syndrome may also occur. These, too, are potentially life threatening and call for immediate medical attention. Genetic testing prior to starting on carbamazepine may predict patients at higher risk for this reaction, which is more common in people with Asian ancestry.
Blood tests are needed to detect kidney failure, liver enzyme elevations, and blood disorders. Report any symptoms to your physician immediately.
Interactions
A large number of over-the-counter and prescription medications may interact with carbamazepine in a dangerous way.
Some drugs, such as clarithromycin, erythromycin or propoxyphene (Darvon), can make carbamazepine much more toxic, with dangerous blood levels building up surprisingly quickly.
Other anticonvulsants interact with carbamazepine in complicated ways and may even reduce its effectiveness. A person who needs several anticonvulsants should be under the care of an experienced epilepsy specialist.
In addition, carbamazepine can interfere with the benefits of many other compounds.
Just a few of the many drugs that interact with Tegretol include several different kinds of antidepressant, the blood thinner warfarin (Coumadin), the ulcer drug cimetidine, the heart and blood pressure pills diltiazem or verapamil (Calan SR, Covera-HS, Verelan), and certain antibiotics such as tetracycline, Vibramycin and INH.
Other medications that may cause problems include antiviral drugs used to treat hepatitis or HIV, MAO inhibitor antidepressants, the anticancer drug procarbazine (Matulane) and the antifungal drug voriconazole (Vfend).
The herb St. John’s wort might speed elimination of carbamazepine from the body, which could reduce its effectiveness.
Psyllium can affect the absorption of carbamazepine; if you take it, it is best to do so at least an hour after taking the anticonvulsant.
Do not take any other medications or herbs without first checking with your physician and pharmacist.
Special Precautions
Some people should not take carbamazepine.
Elderly patients may be especially susceptible to side effects of confusion, agitation or even psychosis.
People with glaucoma, heart disease, kidney problems, liver damage, lupus or a history of blood disorders should take Tegretol only under close medical supervision, if at all.
This medicine can produce a dangerous anemia or blood disorder that can be life-threatening. Periodic blood tests, particularly during the first two months, are crucial to reduce the risk of this hazard.
Pregnant women should use carbamazepine only after careful evaluation and discussions with an obstetrician.
Anticonvulsants in general have the potential to cause birth defects.
Taking the Medicine
Carbamazepine is best absorbed when it is taken with meals. This should also reduce the likelihood of stomach upset.
To maintain its effectiveness, this medicine should be stored in a tightly closed container away from heat and humidity.
Stopping it abruptly could lead to seizures and should be avoided.
